The present invention relates to a circuit breaker such as an integrated circuit breaker and a protective switch integrated in a molded case. More specifically, the present invention relates to a terminal cover of a low-voltage circuit breaker for covering a terminal part.
In a circuit breaker, an external wire is connected to a terminal part directly or with a ring type compression terminal lug or a rod type lug. FIG. 6 is a perspective view showing a three-pole circuit breaker in which a wire is connected via a ring type compression terminal lug at an end of the circuit breaker. In FIG. 6, terminals parts 3 are disposed at front and rear ends of a molded case comprised of a case 1 and a cover 2 (in FIG. 6, only an end of the terminal part 3 at a power supply side is shown). Each of the terminal parts 3 is provided with a terminal 5 for each pole and a terminal screw 4. When an electric wire 7 is connected to the terminal 5 via the ring type compression terminal lug 6, the terminal screw 4 is inserted through the ring type compression terminal lug 6 as shown in FIG. 6, and the terminal screw 4 is screwed into a screw hole 8.
In the circuit breaker with such a connection structure, an upper part of the terminal part 3 must be opened as shown in FIG. 6. Therefore, it is difficult to protect the connection part, or an energized part, of the terminal part 3 from contact. In case that it is necessary to protect the energized part from contact, an additional terminal cover may be attached to the circuit breaker, for example, as disclosed in Japanese Utility Model Publication (KOKAI) No. 57-167549.
FIGS. 7(A) to 7(C) illustrate a circuit breaker with terminal parts covered with a cover, wherein FIG. 7(A) is a plan view thereof, FIG. 7(B) is a side view thereof, and FIG. 7(C) is a front view showing the power supply side of the circuit breaker. In FIGS. 7(A)-7(B), terminal parts 3 to be connected to a power supply and a load are respectively disposed at front and rear ends of a case 1. A control mechanism section such as a switching mechanism for switching a movable contact (not shown) and an over-current tripping mechanism is provided between the front and rear terminal parts 3. In this circuit breaker, the terminal parts 3 are entirely covered with a cover 2. Therefore, it is not possible to connect an electric wire with the ring type compression terminal lug to the terminal part 3. Instead, an electric wire (not shown) is inserted into an electric wire inlet 12 formed at an end face of the case 1 (refer to FIG. 7(C)), and the terminal screw 4 directly fastens the wire to the terminal 5 via a washer 13. In this case, the cover 2 protects the energized part of the terminal part 3 from contact.
In order to transmit a switch signal, a trip signal, and the like from the circuit breaker to external apparatuses, an attachment such as an auxiliary contact device or an alarm contact device may be mounted on the circuit breaker. The attachment is mounted on the circuit breaker by the method shown in FIGS. 7(A)-7(C) or a method disclosed in Japanese Patent Publication (KOKAI) No. 07-169355. More specifically, at one side of the cover 2, i.e. on the power supply side, two openings 9 are formed at the right and left sides adjacent to the control mechanism section. An attachment 10 is attached to the opening to interconnect with the control mechanism section. In case that the attachment 10 is unnecessary, the openings 9 are closed with lids 11.
According to the conventional device described above, the energized part is exposed in the circuit breaker as shown in FIG. 6, in which a wire with the ring type compression terminal lug can be connected. Thus, it is necessary to attach the terminal cover to the circuit breaker in addition to the cover for covering the circuit breaker to protect the energized part from contact. In the circuit breaker shown in FIGS. 7(A)-7(C), in which the terminal parts are integrally covered with the covers, it is difficult to connect the wire with the ring type compression terminal lug to the terminal part. Further, in the circuit breaker shown in FIGS. 7(A)-7(C), in which the attachment is mounted on the cover, it is necessary to close the openings formed in the cover with the lids in the case where the attachment is unnecessary.
It is therefore an object of the present invention to provide a circuit breaker in which the electric wire with or without the ring type compression terminal lug can be connected.
Another object of the invention is to provide a circuit breaker which can cope with both cases that the energized parts are required to be protected from contact or not.
A further object of the invention is to provide a circuit breaker as stated above, wherein an attachment is also mounted on a cover.
Further objects and advantages of the invention will be apparent from the following description of the invention.